forc-doc: Preserve all doc links when merging parallel results (#7379)

## Description
The sway-lib-std docs are broken and not showing all of the generated
documentaiton. The root `index.html` was showing only one module while
`all.html` listed only a subset of types. This started happening after
the parallel processing was introduced in #7296. This PR fixes this as
can be seen in the screenshots below.

Also undoes the CI changes in #7362 & #7365 as they aren't necessary as
this was the root cause.

- Root cause: Using BTreeMap::extend to merge per-item results overwrote
existing per-category vectors, so only the last chunk from parallel
processing survived.
- Fix: replace `.extend` merges with per-key append-and-dedup loops.

Before:
<img width="1608" height="1040" alt="before"
src="https://github.com/user-attachments/assets/e433fcc2-cce6-4737-8ed3-c9e2a679de5a"
/>

After:
<img width="1608" height="1040" alt="after"
src="https://github.com/user-attachments/assets/c9e9c007-df6a-49b3-b864-e30d19f487f2"
/>

## Checklist

- [x] I have linked to any relevant issues.
- [x] I have commented my code, particularly in hard-to-understand
areas.
- [ ] I have updated the documentation where relevant (API docs, the
reference, and the Sway book).
- [ ] If my change requires substantial documentation changes, I have
[requested support from the DevRel
team](https://github.com/FuelLabs/devrel-requests/issues/new/choose)
- [ ] I have added tests that prove my fix is effective or that my
feature works.
- [ ] I have added (or requested a maintainer to add) the necessary
`Breaking*` or `New Feature` labels where relevant.
- [x] I have done my best to ensure that my PR adheres to [the Fuel Labs
Code Review
Standards](https://github.com/FuelLabs/rfcs/blob/master/text/code-standards/external-contributors.md).
- [x] I have requested a review from the relevant team or maintainers.

Author: JoshuaBatty

.github/workflows/gh-pages.yml

@@ -55,20 +55,12 @@ jobs:
       - name: Build Sway std library
         run: forc doc --path ./sway-lib-std
 
-      - name: Move assets into std directory  
-        run: |
-          mv ./sway-lib-std/out/doc/static.files ./sway-lib-std/out/doc/std/
-          mv ./sway-lib-std/out/doc/search.js ./sway-lib-std/out/doc/std/
-          # Fix relative paths in HTML files
-          find ./sway-lib-std/out/doc/std -name "*.html" -type f -exec sed -i 's|../static\.files/|static.files/|g' {} \;
-          find ./sway-lib-std/out/doc/std -name "*.html" -type f -exec sed -i 's|../search\.js|search.js|g' {} \;
-
       - name: Deploy master std
         uses: peaceiris/actions-gh-pages@v3
         with:
           github_token: ${{ secrets.GITHUB_TOKEN }}
-          publish_dir: ./sway-lib-std/out/doc/std
-          destination_dir: master/std
+          publish_dir: ./sway-lib-std/out/doc
+          destination_dir: master
         if: github.ref == 'refs/heads/master'
 
       - name: Deploy master book
@@ -133,7 +125,7 @@ jobs:
         uses: peaceiris/actions-gh-pages@v3
         with:
           github_token: ${{ secrets.GITHUB_TOKEN }}
-          publish_dir: ./sway-lib-std/out/doc
+          publish_dir: ./sway-lib-std/out/doc/std
           destination_dir: ${{ steps.branch_name.outputs.BRANCH_NAME }}/std
         if: startsWith(github.ref, 'refs/tags')
 

forc-plugins/forc-doc/src/render/mod.rs

@@ -120,11 +120,29 @@ impl RenderedDocumentation {
         for (rendered_doc, local_module_map, local_all_docs) in rendered_results? {
             rendered_docs.0.push(rendered_doc);
 
+            // Merge module maps without overwriting existing categories; append and dedup links.
             for (key, value) in local_module_map {
-                module_map.entry(key).or_default().extend(value);
+                let entry = module_map.entry(key).or_default();
+                for (block, mut links) in value {
+                    let list = entry.entry(block).or_default();
+                    // Append new links while avoiding duplicates.
+                    for link in links.drain(..) {
+                        if !list.contains(&link) {
+                            list.push(link);
+                        }
+                    }
+                }
             }
 
-            all_docs.links.extend(local_all_docs.links);
+            // Merge "all docs" links similarly, preserving existing items.
+            for (block, mut links) in local_all_docs.links {
+                let list = all_docs.links.entry(block).or_default();
+                for link in links.drain(..) {
+                    if !list.contains(&link) {
+                        list.push(link);
+                    }
+                }
+            }
         }
 
         // ProjectIndex